Use a counterweight. If you set the counter weight just right, it will
stay down and locked and up and locked. Much safer than using springs.
I'd start with a counter weight post on each end, center of mass about
even with the top and 6" in back of the unit. Taller will take less
counter weights but will stick out further in back when open.

monkers wrote:

I am helping a friend build a pig cooker out of a propane tank (about
30" in dia. by 4'long +or-) the lid is pretty heavy and I would like to
make up a spring and cable to help lift it, I just dont know how to
arrange it. Do I have to build a "mast" that would be higher than the
height of the door in the opened position, with a cable attached to the
door and going over a pulley connected to a spring with a turnbuckle?
How big of a spring should I use? I can connect it to the frame of the
cooker. Will it work without making the "mast" sticking up in mid air?
What about a pulley mounted behind the lid, attached to the spring? Any
help would be great.
Thank you,
Craig